Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019158 (hepatitis)
 30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hepatitis delta virus (HDV) is an RNA virus whose replication and transcription are considered to proceed via RNA-dependent RNA synthesis by RNA polymerase II (Pol II), and the viral protein called hepatitis delta antigen (HDAg) is essential for these processes. HDAg was previously shown to stimulate Pol II elongation on both DNA and RNA templates in vitro. Here, the mechanism of elongation control by HDAg was investigated because it serves as a prototype of cellular transcription elongation factors and also plays an interesting role in HDV proliferation. With site-specific photocrosslinking and transcription using reconstituted elongation complexes, evidence is presented that HDAg functionally interacts with the clamp of Pol II, a mobile structure that holds DNA and RNA in place. Strikingly, HDAg not only increases the rate of elongation but also affects the decision of which nucleotide is incorporated. These and our previous findings lead us to propose a model in which HDAg interacts with and loosens the clamp, and thereby accelerates forward translocation of Pol II at the cost of fidelity. By reducing transcriptional fidelity in terms of not only discrimination of incoming nucleotides but also recognition of templates, HDAg may facilitate the unusual RNA-dependent RNA synthesis by Pol II.
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PMID:Hepatitis delta antigen binds to the clamp of RNA polymerase II and affects transcriptional fidelity. 1758 98

Previous studies have indicated that the replication of the RNA genome of hepatitis delta virus (HDV) involves redirection of RNA polymerase II (Pol II), a host enzyme that normally uses DNA as a template. However, there has been some controversy about whether in one part of this HDV RNA transcription, a polymerase other than Pol II is involved. The present study applied a recently described cell system (293-HDV) of tetracycline-inducible HDV RNA replication to provide new data regarding the involvement of host polymerases in HDV transcription. The data generated with a nuclear run-on assay demonstrated that synthesis not only of genomic RNA but also of its complement, the antigenome, could be inhibited by low concentrations of amanitin specific for Pol II transcription. Subsequent studies used immunoprecipitation and rate-zonal sedimentation of nuclear extracts together with double immunostaining of 293-HDV cells, in order to examine the associations between Pol II and HDV RNAs, as well as the small delta antigen, an HDV-encoded protein known to be essential for replication. Findings include evidence that HDV replication is somehow able to direct the available delta antigen to sites in the nucleoplasm, almost exclusively colocalized with Pol II in what others have described as transcription factories.
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PMID:Transcription of hepatitis delta virus RNA by RNA polymerase II. 1803 11

Systemic lupus erythematosus (SLE) is an autoimmune connective tissue disease, where vascular lesions are one of the typical symptoms. The pathological process often involves skin vessels, renal glomeruli, the cardiovascular system, brain, lung alveoli, and gastrointestinal tract vessels. This review presents possible adverse mechanisms underlying the cause and effect relationship of various factors causing vascular lesions in SLE patients. The generally accepted hypothesis links vascular damage in SLE with the deposition of immune complexes in the vascular endothelium. The anti-endothelial cell antibodies (AECA), antiphospholipid antibodies and anti-double stranded DNA antibodies present in SLE, that directly or indirectly affect endothelial cells, causing inflammatory damage to the vessel wall, and their role, have been discussed. It has been stressed that although the suggested role of AECA in vasculitis pathogenesis has not been fully established, evidence, however, has demonstrated that AECA is a factor causing endothelial damage in SLE patients. On the other hand, issues concerning cellular adhesion molecules which enable leukocyte adhesion and rolling along the endothelial cell surface, and their extravascular migration, focus on the role they may be playing in SLE patients with vasculitis. A potential role of soluble forms of adhesion molecules, pentraxin 3, medications, infections in the pathogenesis of this disease has also been shown. Special attention has been given to the role of type 3 hepatitis virus in vascular damage in SLE.
Pol Arch Med Wewn
PMID:Vasculopathy and vasculitis in systemic lupus erythematosus. 1840 74

A hiccup is involuntary, paroxysmal inspiratory movements of the chest wall associated with diaphragm and accessory respiratory muscle contractions, with the synchronized closure of glottis. The mechanism underlying this common primitive reflex plays an important role in protecting airways against esophageal aspiration. The hiccup reflex mechanism is based on the afferent pathway (vagus and phrenic nerve and sympathetic fibers innervating chest organs, the abdomen, the ear, the nose and the throat stimulation, and the stimulation of hiccup center in the central nervous system, mainly reflecting psychogenic or metabolic disorders) and the efferent pathway (phrenic nerves). An incidental hiccup is a common problem, usually resolves spontaneously and does not present a clinical issue. The clinical issue arises in the case of pathologic persistent hiccups or symptomatic secondary hiccups which may lead to significant fatigue, insomnia or depression. Generally, pathologic hiccups are associated with considerable discomfort concerning both the "stigmatized" person and his or her personal surroundings in which it evokes different emotions, from amusement through impatience to uneasiness and the suggestion of a medical visit as an expression of concern for a given person. The most common causes of pathologic symptomatic hiccups are nervous system diseases, either the central nervous system (proliferative, angiogenic, inflammatory disorders), or the peripheral nervous system: the irritation of the phrenic nerve (proliferative disorders, goitre) and the vagus nerve (otolaryngologic diseases, meningitis, esophageal, stomach and duodenal diseases, hepatitis, pancreatitis, enteritis). The vagus nerve irritation with subsequent hiccups may be caused by chest disorders (injury, surgery) and heart diseases (myocardial infarction). In the present paper we describe the case of a 62-year-old male with recurrent hiccups associated with exertion as a secondary symptom of myocardial ischemia.
Pol Arch Med Wewn 2008 Mar
PMID:Hiccups as a myocardial ischemia symptom. 1847 62

The evolutionary origin of human hepatitis delta virus (HDV) replication by RNA-directed transcription is unclear. Here we identify two species of 5'-capped, approximately 18-25-nucleotide small RNAs. One was of antigenomic polarity, corresponding to the 5' end of hepatitis delta antigen (HDAg) mRNA, and interacted with HDAg and RNA polymerase II (Pol II), whereas the other mapped to a structurally analogous region on the genomic RNA hairpin. An HDAg-interaction screen indicated that HDAg interacts with MOV10, the human homolog of the Arabidopsis thaliana RNA amplification factor gene SDE3 and Drosophila melanogaster RISC-maturation factor gene Armitage (armi). MOV10 knockdown inhibited HDV replication, but not HDAg mRNA translation, further supporting a role for MOV10 in RNA-directed transcription. Together, our studies define RNA hairpins as critical elements for the initiation of HDV-related, RNA-directed transcription. The identification of capped small RNAs and the involvement of MOV10 in HDV replication further suggest a conserved mechanism related to RNA-directed transcription in lower eukaryotes.
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PMID:Capped small RNAs and MOV10 in human hepatitis delta virus replication. 1855 26

Ticlopidine, a thienopyridine derivative, is widely used in Poland in vascular procedures. Ticlopidine-induced acute cholestatic hepatitis is a very rare adverse reaction. We present a case of a patient with possible ticlopidine-induced cholestatic hepatitis occurring a few days after introducing this drug.
Kardiol Pol 2008 Jul
PMID:[Cholestatic hepatitis as a ticlopidine-induced complication of treatment - a case report]. 1869 May 67

Hepatitis delta virus (HDV) encodes one protein, hepatitis delta antigen (deltaAg), a 195-amino-acid RNA binding protein essential for the accumulation of HDV RNA-directed RNA transcripts. It has been accepted that deltaAg localizes predominantly to the nucleolus in the absence of HDV genome replication while in the presence of replication, deltaAg facilitates HDV RNA transport to the nucleoplasm and helps redirect host RNA polymerase II (Pol II) to achieve transcription and accumulation of processed HDV RNA species. This study used immunostaining and confocal microscopy to evaluate factors controlling the localization of deltaAg in the presence and absence of replicating and nonreplicating HDV RNAs. When deltaAg was expressed in the absence of full-length HDV RNAs, it colocalized with nucleolin, a predominant nucleolar protein. With time, or more quickly after induced cell stress, there was a redistribution of both deltaAg and nucleolin to the nucleoplasm. Following expression of nonreplicating HDV RNAs, deltaAg moved to the nucleoplasm, but nucleolin was unchanged. When deltaAg was expressed along with replicating HDV RNA, it was found predominantly in the nucleoplasm along with Pol II. This localization was insensitive to inhibitors of HDV replication, suggesting that the majority of deltaAg in the nucleoplasm reflects ribonucleoprotein accumulation rather than ongoing transcription. An additional approach was to reevaluate several forms of deltaAg altered at specific locations considered to be essential for protein function. These studies provide evidence that deltaAg does not interact directly with either Pol II or nucleolin and that forms of deltaAg which support replication are also capable of prior nucleolar transit.
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PMID:Intracellular localization of hepatitis delta virus proteins in the presence and absence of viral RNA accumulation. 1936 24

Reverse genetics systems for generating recombinant influenza viruses are based on two different mechanisms for obtaining the 3' end of the viral RNA: one uses the self-cleaving hepatitis delta virus ribozyme (HDVR), and the other uses the murine RNA polymerase I (Pol I) terminator. In this study, we employed EGFP and Renilla luciferase reporter constructs to compare the efficiency of both methods. Our results indicate that the murine Pol I terminator was more efficient than the HDVR, which will be helpful in choosing an influenza virus rescue system, as well as in establishing other RNA virus rescue systems.
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PMID:The mouse Pol I terminator is more efficient than the hepatitis delta virus ribozyme in generating influenza-virus-like RNAs with precise 3' ends in a plasmid-only-based virus rescue system. 1952 91

We investigated whether a continuous transcript is necessary for co-transcriptional pre-mRNA processing. Cutting an intron with the fast-cleaving hepatitis delta ribozyme, but not the slower hammerhead, inhibited splicing. Therefore, exon tethering to RNA polymerase II (Pol II) cannot rescue splicing of a transcript severed by a ribozyme that cleaves rapidly relative to the rate of splicing. Ribozyme cutting also released cap-binding complex (CBC) from the gene, suggesting that exon 1 is not tethered. Unexpectedly, cutting within exons inhibited splicing of distal introns, where exon definition is not affected, probably owing to disruption of the interactions with the CBC and the Pol II C-terminal domain that facilitate splicing. Ribozyme cutting within the mRNA also inhibited 3' processing and transcription termination. We propose that damaging the nascent transcript aborts pre-mRNA processing and that this mechanism may help to prevent association of processing factors with Pol II that is not productively engaged in transcription.
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PMID:Fast ribozyme cleavage releases transcripts from RNA polymerase II and aborts co-transcriptional pre-mRNA processing. 1973 89

Drug-induced hypersensitivity syndrome (DIHS) is characterized by fever, rash and internal organ involvement, mostly in form of hepatitis, myocarditis, nephritis or pneumonitis, which may occur 1-8 weeks after medicine exposure. Fever is an early feature, usually preceding a widespread erythematous skin eruption, but the severity of the skin-related changes does not correlate with the extent of internal organ involvement. It is considered that anticonvulsants (particularly carbamazepine), antibiotics, allopurinol are the most frequent causative agents of DIHS. The underlying mechanisms causing DIHS are poorly understood--defective detoxification of the reactive drug's metabolites or genetic predisposition have been implicated. Diagnosis of DIHS is based on clinical presentation connected with drug intake, supported by a finding of eosinophilia, increased concentration of inflammation markers and abnormal biochemical parameters, mainly liver function tests. Treatment consists of immediate withdrawal of all suspected medicines, followed by supportive systemic corticosteroids. We describe a case of a 72-years-old female who developed symptoms of drug-induced hypersensitivity syndrome after approximately 4 weeks of taking anticonvulsant (Amizepin) due to sensual axonal polyneuropathy. Withdrawal of drug and treatment with systemic corticosteroids caused clinical improvement rapidly.
Pneumonol Alergol Pol 2011
PMID:[Drug-induced hypersensitivity syndrome--a literature review and the case report]. 2119 Jan 54


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